Bacterial activity in South Pole snow

• Main Authors: Edward J. Carpenter, Senjie Lin, Douglas G. Capone
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2000
• Subjects: Antarctic; Austral; Lake Vostok; South Pole; The Antarctic; Antarc*; South pole
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.488.4406; http://www.phytoplankton.uconn.edu/publications/20.pdf

Large populations (200 to 5,000 cells ml21 in snowmelt) of bacteria were present in surface snow and firn from the south pole sampled in January 1999 and 2000. DNA isolated from this snow yielded ribosomal DNA sequences similar to those of several psychrophilic bacteria and a bacterium which aligns closely with members of the genus Deinococcus, an ionizing-radiation- and desiccation-resistant genus. We also obtained evidence of low rates of bacterial DNA and protein synthesis which indicates that the organisms were metabolizing at ambient subzero temperatures (212 to 217°C). There are no reports which document active metabolism of bacteria in the surface snow of the interior of the Antarctic continent. At the south pole, temperatures are extreme and austral winter air temperatures reach about 285°C, while in summer it can warm to about 213°C (mean monthly air tem-perature in December is 226°C). Bacteria have previously been cultured from samples taken from Antarctic ice cores (1), and deep cores from the accreted ice above subglacial Lake Vostok revealed a high diversity (24) of species that were reported to be metabolically active when warmed to 3°C (16). We report here bacterial populations and associated metabolic activity in surface (upper 20 cm) snow and firn collected at the south pole in the austral summer. Sampling. Snow samples were collected on 9 and 18 January